A Reddit user named Cranbourne--who claims to be a Microsoft dev--says the number skip most likely was in reaction to shorthand used by programmers back in the era of Windows 95 and 98. Essentially, the coders would write "Windows 9x" to refer to either of those Windows versions.

Exit Theatre Mode

Windows 95 and 98, at one time, were absolutely everywhere. And believe it or not, if you dig hard enough, you may even find businesses or manufacturing operations still using it. But more importantly, as those third-party software programs were updated over the years, the code snippet could still be present. And if the OS is suddenly also called Windows 9--well, you see the possibilities for compatibility trouble.

We're not sure if this is the official reason, but it seems far more plausible than some of the other theories (including some weak math involving "major" Windows releases). Windows 10 is due out later next year.

Matt Clark is a freelance writer covering the world of videogames, tech, and popular culture. Follow him on Twitter @ClarkMatt and MyIGN at Matt_Clark.